Playtest info from someone who was lucky to try the demo!! -->
"Sorry if this is long and unorganized. I’m super exhausted!
I got a chance to play one round of a demo game today at Gencon. It was excellent and I tried to ask everything I could think of.
The expansion seems to include four “modules” although I am not sure that they are all independent of one another.
House Arryn
The simplest is the inclusion of House Arryn, along with all of the pieces, tokens, cards, etc. Not sure if cards are the same as Feast for Crows, but you shouldn’t need Feast (and you could totally use these pieces when playing Feast of course). Also includes an overlay for the vale region which is probably improved.
I assume you can play without Arryn and just leave the overlay out, but I see no reason not to play them if you’ve got them...
House Targaryen
House Targaryen comes with the Essos board (FFG rep said you don’t use the Essos board if nobody plays Targ) and is mechanically a little different than other houses.
First, Targ starts with three dragons. Dragons start at 0 str but every even-numbered round the strength permanently increases by one! In addition, dragons can move to ANY location on the board when they march! Targaryen will likely be an extreme threat late in the game.
Secondly, Targ is ALWAYS in lowest spot in every track, although their spot on King’s Court does grant them some stars (two I think). FFG guy said they can still bid in Clash of Kings and they just add their bid to a house of their choice - it didn’t happen in our game so I don’t know how/when they choose.
Finally, Targ does not score points by controlling castles. Instead, there is a forth Westeros deck. The cards in this deck place loyalty tokens in Westeros (usually someone can influence where it goes, depending on the card text). Targaryen scores by occupying these specific spaces.
Vassal Houses
One of the coolest parts of the expansion. When playing with Vassal houses, you set up every House including those not being played (exception, you don’t use Targ as a vassal - just leave them out if nobody plays them)
The setup for vassals are different than those of player houses (probably stronger since they kind of double as neutral forces, but I think fewer ships - with some vassal houses not getting ships at all I think).
Each round, players would choose vassals in turn order. I think you could pass and get something else, but I’m not sure.
Players in command of a vassal got five neutral tokens they could use for that house, and could not attack their vassal, but could use their vassal to attack other players, support, etc.
Combat involving vassals had players drawing three cards from a deck of neutral house cards, and choosing one.
The vassal houses did not seem to gain power but I assume their controller would be able to muster.
It was unclear in the demo how the vassals are placed on the tracks (if they are at all, and if not, how their turn order works). Because of the nature of the demo, the organizer was just “vassalizing” houses that dropped and also letting people jump in and start playing as them. He mentioned you can vassalize a player house if the player has to leave the game - not sure if it’s “official” but it seems a decent enough rule.
Iron Bank
Finally, the game added an Iron Bank. Players have three additional order tokens that can ONLY function in sea spaces (maybe ports?) Two are regular March and one is a star order with a stack of coins. This is resolved during consolidate power and allows the owner to buy one of three advantage cards priced depending on which spot it’s end.
You’d pay power to get the card, and then keep the card. Every turn you’d have to pay one more power or lose a unit. The cards I saw gave a huge amount of one-time power, a huge amount of figures, and something to allow manipulation of the Westeros decks which I didn’t understand.
Final Thoughts
The vassal idea and the different “scenarios” it can create at different player counts has me very interested.
It’s hard to see what it will do to game balance (especially as I played one round, and the organizer was playing fast and loose and mostly trying to just give people a feel for the game - many of whom never played base game)
My gut feeling is that vassals create huge importance for the iron throne (I think this might be problematic and could probably be handled as a separate bid - potentially even bidding for every vassal individually). This, along with the iron bank, make power tokens tremendously more valuable.
That might bode well for players who want to act diplomatically, protect their borders, and secure power.
The vassal mechanic in general could be very helpful for houses like Lannister (if Greyjoy and/or Tyrell are vassals).
The presence of Targaryen also will potentially shake up the game in the east, with one more naval force battling for the seas.
It’s also possible there are new setups for existing houses to help balance and accommodate for the two new houses , but I’m not sure (I didn’t see any such game materials although there were definitely cards with vassal setup instructions)"
Source:
https://boardgamegeek.com/article/29679744#29679744 
